气候变化领域集成服务门户(CCPortal): Transformation and ageing of biomass burning carbonaceous aerosol over tropical South America from aircraft in situ measurements during SAMBBA

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DOI	10.5194/acp-20-5309-2020
	Transformation and ageing of biomass burning carbonaceous aerosol over tropical South America from aircraft in situ measurements during SAMBBA
	Morgan W.T.; Allan J.D.; Bauguitte S.; Darbyshire E.; Flynn M.J.; Lee J.; Liu D.; Johnson B.; Haywood J.; Longo K.M.; Artaxo P.E.; Coe H.
发表日期	2020
ISSN	1680-7316
起始页码	5309
结束页码	5326
卷号	20 期号:9
英文摘要	We present a range of airborne in situ observations of biomass burning carbonaceous aerosol over tropical South America, including a case study of a large tropical forest wildfire and a series of regional survey flights across the Brazilian Amazon and Cerrado. The study forms part of the South American Biomass Burning Analysis (SAMBBA) project, which was conducted during September and October 2012. We find limited evidence for net increases in aerosol mass through atmospheric ageing combined with substantial changes in the chemical properties of organic aerosol (OA). Oxidation of the OA increases significantly and rapidly on the scale of 2.5-3 h based on our case study analysis and is consistent with secondary organic aerosol production. The observations of limited net enhancement in OA coupled with such changes in chemical composition imply that evaporation of OA is also occurring to balance these changes.We observe significant coatings on black carbon particles at source, but with limited changes with ageing in both particle core size and coating thickness. We quantify variability in the ratio of OA to carbon monoxide across our study as a key parameter representing both initial fire conditions and an indicator of net aerosol production with atmospheric ageing. We observe ratios of 0.075-0.13 μgsm-3 ppbv-1 in the west of our study region over the Amazon tropical forest in air masses less influenced by precipitation and a value of 0.095 μgsm-3 ppbv-1 over the Cerrado environment in the east (where sm-3 refers to standard metre cubed). Such values are consistent with emission factors used by numerical models to represent biomass burning OA emissions. Black carbon particle core sizes typically range from mean mass diameters of 250 to 290 nm, while coating thicknesses range from 40 to 110 nm in air masses less influenced by precipitation. The primary driver of the variability we observe appears to be related to changes at the initial fire source. A key lesson from our study is that simply aggregating our observations as a function of atmospheric ageing would have been misleading due to the complex nature of the regional aerosol and its drivers, due to the many conflating and competing factors that are present. Our study explores and quantifies key uncertainties in the evolution of biomass burning aerosol at both near-field and regional scales. Our results suggest that the initial conditions of the fire are the primary driver of carbonaceous aerosol physical and chemical properties over tropical South Amer-ica, aside from significant oxidation of OA during atmospheric ageing. Such findings imply that uncertainties in the magnitude of the aerosol burden and its impact on weather, climate, health and natural ecosystems most likely lie in quantifying emission sources, alongside atmospheric dispersion, transport and removal rather than chemical enhancements in mass. © 2020 BMJ Publishing Group. All rights reserved.
语种	英语
scopus关键词	aerosol composition; aging; airborne survey; biomass burning; carbon; in situ measurement; transformation; Amazonas [Brazil]; Brazil
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/141369
作者单位	Department of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom; National Centre for Atmospheric Science, University of Manchester, Manchester, United Kingdom; Facility for Airborne Atmospheric Measurements, Cranfield University, Cranfield, United Kingdom; Department of Chemistry, University of York, York, United Kingdom; Met Office, Exeter, United Kingdom; College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom; National Institute for Space Research (INPE), São José dos Campos, Brazil; Physics Institute, University of São Paulo, São Paulo, Brazil; NASA Goddard Space Flight Center and USRA/GESTAR, Greenbelt, MD, United States
推荐引用方式 GB/T 7714	Morgan W.T.,Allan J.D.,Bauguitte S.,et al. Transformation and ageing of biomass burning carbonaceous aerosol over tropical South America from aircraft in situ measurements during SAMBBA[J],2020,20(9).
APA	Morgan W.T..,Allan J.D..,Bauguitte S..,Darbyshire E..,Flynn M.J..,...&Coe H..(2020).Transformation and ageing of biomass burning carbonaceous aerosol over tropical South America from aircraft in situ measurements during SAMBBA.Atmospheric Chemistry and Physics,20(9).
MLA	Morgan W.T.,et al."Transformation and ageing of biomass burning carbonaceous aerosol over tropical South America from aircraft in situ measurements during SAMBBA".Atmospheric Chemistry and Physics 20.9(2020).